The contemplation of the nine stages of a decaying corpse is a Buddhist meditational practice in which the practitioner imagines or observes the gradual decomposition of a dead body.
[2]: 295 Early instances of the nine stages of decay can be found in the Satipaṭṭhāna Sutta,[3] (–20 BC) the "Sutra on the Samādhi Contemplation of the Oceanlike Buddha," and the "Discourse on the Great Wisdom" (Mahaprajnaparamitita-sastra) by Nagarjuna (c. 150–250 AD).
The stages listed in the Mahaprajnaparamitita-sastra spread to Japan, probably through Chinese Tiantai writings including the Mohe Zhiguan of Zhiyi (438–497 AD),[4] and influenced medieval Japanese art and literature.
'nine horrible notions,'[5] and lists them as follows:[6][1]: 24 Various techniques of meditation on the process of bodily decay date back to early Buddhism, originating in India.
[6] Buddhist sources also suggest that real corpses were originally observed as part of the practice, without the practitioner relying on pure imagination.
[1]: 25 kusōzu gained aesthetic significance in addition to their meditative function as impermanence (無常 mujou) was already a major feature of Japanese art and literature.
[2]: 277 There are a large number of kusōzu still being used in religion in Japan,[2]: 279 and Japanese artists such as Fuyuko Matsui have continued the theme of the nine stages into the 21st century.
Some kusōzu such as the Jindou fujou souzu (人道不浄相図)[11] present the decay of the female corpse in the context of the nature, "amidst a world of seasonal trees, flowers, and other flora."
[2]: 282 Although the subjects of kusōzu are typically anonymous noblewomen, there are many that are explicitly intended to depict the Heian Waka poet Ono no Komachi (小野小町).
[2]: 296 These depictions of Komachi are related to a tradition of literature that emphasises the contrast between her physical beauty during her youth, and her ageing and poverty at the end of her life.
肪脹新死名叵言 既經七日貌纔存 紅顏暗變失花麗 玄鬢先衰纏草根 六腑爛壞餘棺槨 四肢洪直臥郊原 郊原寂寞無隨者 獨趣冥途中有魂 The distension makes the newly deceased hard to identify; After only seven days, mere vestiges of the [original] appearance remain.
Genshin, a Buddhist affiliated with Pure Land school, wrote the work Ōjōyōshū in which he put the kusōzu in a doctrinal and functional context for the purpose of contemplating the nine stages of decay in connection to the six paths that a being can reincarnate into.